If you consider that a pixel is a container for RGB value, then the length and area collapse into simple storage requirement. When an image is some px wide and

If you consider that a pixel is a container for RGB value, then the length and area collapse into simple storage requirement. When an image is some px wide and some px high, it provides a shape (ratio between them), because a camera of 12mega px isn't 1px x 12M px in shape, but it does occupy 12M storage units nevertheless. I agree though that like many IT related terms, their usage is twisted and simplified to amplify the buzz. Because it is more marketing friendly to put a bigger number than exact dimensions and proper terminology.